1. Technical Field
The present invention is related generally to monoclonal antibodies. More particularly, the present invention is related to monoclonal antibodies against human Pneumocystis carinii.
2. State of the Art
Pneumocystis carinii is an organism that causes pneumonia in immunocompromised patients. Hence, it is a major pathogen in patients with the acquired immunodeficiency syndrome (AIDS) as well as in patients with a variety of other humoral and cell-mediated immunologic abnormalities (Kovaos, et al., Ann Intern Med 1984 100:663-71). Since 1981, over 10,000 cases of P. carinii pneumonia have been reported to the Centers for Disease Control and current projections estimate that, in 1986 alone, there will be an additional 10,000 cases in the United States (CDC. Update: Acquired immunodeficiency syndrome--United States. MMWR 1986. 35:17-21). Because the organism cannot be cultured from humans, and because no reliable assay for detection of antigen exists, diagnosis at present relies on the use of special stains, such as methenamine silver, toluidine blue-O, or Giemsa, to detect the organism in pulmonary specimens (Gosey, et al. J Clin Micro 1985. 22:803-7. Hughes W T. CRC Crit Rev Clin Lab Sci 1975. p. 145-170). These stains are often time-consuming to perform, may require extensive and methodical evaluation of the specimens, and require experienced personnel for correct interpretation.
Although immunologic stains such as immunofluorescence are potentially rapid and easy to interpret, attempts at applying such techniques to the diagnosis of P. carinii pneumonia have been disappointing (Lim, et al. Apl Micro 1974. 27:144-9). Because purified P. carinii cannot be obtained from lung tissues, hyperimmune sera obtained from immunized animals have lacked the specificity necessary for a diagnostic assay. Use of a monoclonal antibody specific for human P. carinii could certainly help the development of a more reliable diagnostic assay.
However, monoclonal antibodies having specific binding affinity to human P. carinii have not heretofore been obtained